Enteric nerves have been reported to make synaptic contacts with ICC-IM . These contacts include areas of electron dense lining on the inner aspect of the varicosity membrane without any postsynaptic density on the membrane of ICC . Such contacts were not reported between the nerves and the smooth muscles.
32.
The active zone of individual sympathetic varicosities, delineated by a high concentration of syntaxin, occupies an area on the pre-junctional membrane of about 0.2 ?m 2; this gives a junctional gap between the pre-junctional active zone and post-junctional membranes that varies between about 50 and 100 nm.
33.
This is n = [ ln ( 0.5 ) / ln ( 0.981 ) ] / 4, or nH " 9 . If the density of varicosities is around 2.2 per 1000 ?m 3, this number of varicosities should occur within an average range ( radius ) of about 10 ?m ( noting that within such a radius there is a tissue volume of about 4200 ?m 3 ).
34.
This is n = [ ln ( 0.5 ) / ln ( 0.981 ) ] / 4, or nH " 9 . If the density of varicosities is around 2.2 per 1000 ?m 3, this number of varicosities should occur within an average range ( radius ) of about 10 ?m ( noting that within such a radius there is a tissue volume of about 4200 ?m 3 ).
35.
During a five-impulse train, assuming that the last impulse in the train cannot autoinhibit the Ca 2 + influx during the train, the expectation value of n can be found by solving [ ( 1 " 0.019 ) 4n ] = ( 1 " 0.5 ), i . e . the probability that there will be no local release, given n varicosities within the diffusion range.
36.
ATP release ( hence noradrenaline release, if there is strict corelease ) is highly intermittent at these junctions ( Brain et al . 2002 ), with a probability that a given action potential will evoke the release from a given varicosity of only 0.019 . If there are n varicosities within the diffusion range of a particular varicosity, we can consider the number of such varicosities that might need to be present in order that, on average ( using P = 0.5 to give the median value ), neurotransmitter will be released locally.
37.
ATP release ( hence noradrenaline release, if there is strict corelease ) is highly intermittent at these junctions ( Brain et al . 2002 ), with a probability that a given action potential will evoke the release from a given varicosity of only 0.019 . If there are n varicosities within the diffusion range of a particular varicosity, we can consider the number of such varicosities that might need to be present in order that, on average ( using P = 0.5 to give the median value ), neurotransmitter will be released locally.
38.
ATP release ( hence noradrenaline release, if there is strict corelease ) is highly intermittent at these junctions ( Brain et al . 2002 ), with a probability that a given action potential will evoke the release from a given varicosity of only 0.019 . If there are n varicosities within the diffusion range of a particular varicosity, we can consider the number of such varicosities that might need to be present in order that, on average ( using P = 0.5 to give the median value ), neurotransmitter will be released locally.
39.
ATP release ( hence noradrenaline release, if there is strict corelease ) is highly intermittent at these junctions ( Brain et al . 2002 ), with a probability that a given action potential will evoke the release from a given varicosity of only 0.019 . If there are n varicosities within the diffusion range of a particular varicosity, we can consider the number of such varicosities that might need to be present in order that, on average ( using P = 0.5 to give the median value ), neurotransmitter will be released locally.
